1. Field of the Invention
The invention relates to a method for separating whole blood into a leukocyte-depleted erythrocyte concentrate and plasma, and to a device for carrying out this method.
2. Related Technology
In whole-blood separation, whole blood taken from blood donors is separated into the individual blood components. These are principally erythrocyte concentrates or plasma fractions which may be cell-free or contain thrombocytes.
Separation of whole blood nowadays either involves use of specially designed production areas, high-performance centrifuges, blood separation appliances such as plasma filters, and specially trained personnel, or plasma separators are employed for direct recovery of individual or combined blood components.
As a result of the increased quality requirements and the legal regulations, and in view of the high-performance blood separators which have been developed in the meantime, it has become virtually impossible for a transfusion specialist or for quite small hospitals to produce blood products in this way and to sell blood products produced in this way. It would therefore be useful to permit simple separation of blood components in this sector too, without compromising the high quality standards. It would also be useful to be able to produce such blood products on this basis without high investment in technology and thus without excessive costs.
DE 33 02 383 A1 discloses a method and a device for recovering blood plasma in which in vivo whole blood is taken from a patient and is then divided into an erythrocyte concentrate and a plasma fraction in a plasma filter.
In a further configuration, the erythrocyte concentrate is returned to the patient through the plasma filter with renewed separation of a further plasma fraction.
Although double fractionation of plasma is performed here, the erythrocyte concentrate is returned to the blood donor again directly without interim storage.
EP 349 188 describes a method for separating blood into blood components, and a separator unit for recovering these blood components. According to this method, blood is first conveyed from a whole-blood container through a filter which removes leukocytes and also blood platelets. The filtered blood is then collected in a primary bag which is then subjected to centrifugation to divide the blood up into a plasma fraction and an erythrocyte concentrate. The plasma is conveyed through a plasma line into a further plasma bag.
As has already been explained above, this method is technically complex because of the use of a centrifuge. Moreover, the plasma cannot be separated completely, because there may otherwise be a danger of mixing with erythrocytes.
U.S. Pat. No. 5,527,472 likewise describes a closed system for separation of whole-blood constituents by means of centrifugation. In this method, the centrifugation initially takes place in a first bag with division into plasma and an erythrocyte concentrate, to which a substitute solution is then mixed. This mixture is then freed of leukocytes in a leukocyte-removing filter, so that an erythrocyte concentrate with substitute solution is obtained, but which still contains a high proportion of plasma.
This method too is technically complex, and a high proportion of blood plasma remains in the erythrocyte concentrate.
WO 02/13888 discloses a filter arrangement for separating blood into plasma and cellular components using filter type Mikro PSE-TF 10 from Akzo Faser AG. The arrangement is closed off airtight and impervious to microbes. Before separation of the whole blood, leukocytes and thrombocytes are separated off, if appropriate. By reversing the direction of flow through the filter arrangement after the first pass, a hematocrit value of at least 80 can be obtained in the erythrocyte fraction.
WO 02/13888 does not disclose simultaneous separation of whole blood into an erythrocyte concentrate and a thrombocyte-containing plasma.
As a result of this, the object of the invention is to provide a technically simple method for separation of whole blood into an erythrocyte concentrate and a thrombocyte-containing plasma, in which as little plasma as possible remains in erythrocyte concentrate, and which method can be performed directly at the donor site, in particular without any delay after withdrawal.